Former Southampton manager Koeman was recently appointed the new Everton boss.
Yobo, who was on the books of the Toffees from 2003 until 2012 following an initial loan move from Marseille, has backed the Dutchman to succeed at Goodison Park.
The former Nigeria international defender has suggested that the Everton fans should dream of success under Koeman.
The ex-Fenerbahce man has also expressed his sadness at the passing away of former Nigeria coach Shuaibu Amodu.
Took a break since I lost Coach Amodu, mulled over it and convinced @Everton got it right with the appointment of Koeman. So let's dream!— Joseph Yobo (@jyobo234) June 20, 2016
Everton failed to finish in the top 10 of the Premier League last season. The Toffees, though, are a big club in England, and fans will expect the team to challenge for a top-six finish in the league during the 2016-17 campaign.
Koeman is a good manager, and he proved during his time at Southampton that he can work in a limited budget.
It will be interesting to see which players that the Dutchman signs for Everton in the summer transfer window.